Support Conduit application of most CustomField transactions in EditEngine
Summary:
Ref T9132. Give most standard custom fields reasonable Conduit support so you can use the new application.x endpoints to set them.
Major missing field type is dates, again.
Test Plan: Used Conduit to set various custom fields on a package.
Reviewers: chad
Reviewed By: chad
Maniphest Tasks: T9132
Differential Revision: https://secure.phabricator.com/D14635